The present study was undertaken with the aim to evaluate the diversity, the size and the vertical, horizontal and monthly distributions of the soil spiders in a field of cassava. Two methods were used, the" distance sampling" and the “Barber” trap. The identification of spiders was carried out using a binocular magnifying glass and identification key books of the Africa spiders. Each spiders sample was measured at the cephalothorax region with the help of graduated micrometer. The obtained results were analyzed by the mean of khi-square statistic test. 306 specimens of spiders belonging to 7 families, 10 genus and 12 species were harvested and identified. By the mean of "distance sampling" technique, 135 specimens belonging to 2 families and 7 species were captured. Lycosidae family was the most abundant (227 specimens) and the more diversified (4 species out of 7 harvested), following by the Ctenidae family (3 species out of 8 specimens). By the mean of “Barber” trap, 171 specimens belonging to 6 families were captured among which Lycosidae family was also the most abundant with 167 specimens and the more diversified (4 species out of 9 harvested) that the other (Salticidae, Gnaphosidae and Lycosidae). The ecological approach revealed that the spiders in this biotope circulate at the soil level (±0.96 cm) and that they have small sizes (2.07 mm to the level of the cephalothorax). Weeding and/or the ploughing could simplify the agro-systems and thus would involve their colonization by spiders of small sizes essential for the regulation of the population of the devastating insects of the cassava.